The present invention relates to a novel fluorinated resist composition. More particularly, it relates to a chemical amplification type resist composition useful for fine processing employing far ultraviolet rays such as KrF or ArF excimer laser, or vacuum ultraviolet rays such as F2 excimer laser.
In recent years, along with the progress in fine circuit patterns in the process for producing semiconductor integrated circuits, a photoresist material having high resolution and high sensitivity is desired. As the circuit patterns become fine, a short wavelength of a light source for an exposure apparatus becomes essential. In an application to lithography employing an excimer laser of 250 nm or shorter, a polyvinyl phenol type resin, an alicyclic acrylic type resin or a polynorbornene type resin has, for example, been proposed, but no adequate resolution and sensitivity have been obtained.
It is an object of the present invention to provide a resist composition which is particularly excellent in transparency to a radiation and in dry etching properties, as a chemical amplification type resist and which gives a resist pattern excellent in sensitivity, resolution, evenness, heat resistance, etc.
The present invention is the following invention which has been made to solve the above-described problems.
1) A resist composition comprising a fluoropolymer (A) which is a fluoropolymer having repeating units formed by cyclopolymerization of a fluorinated diene represented by the formula (1) and which has blocked acidic groups, provided that in a case where Q is a bivalent organic group having a group which can be converted to a blocked acidic group, said group is converted to a blocked acidic group after the cyclopolymerization, an acid-generating compound (B) which generates an acid under irradiation with light, and an organic solvent (c):
CF2xe2x95x90CR1xe2x80x94Qxe2x80x94CR2xe2x95x90CH2xe2x80x83xe2x80x83(1)
wherein each of R1 and R2 which are independent of each other, is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, and Q is a bivalent organic group having a blocked acidic group capable of forming an acidic group by an acid or a group which can be converted to such a blocked acidic group.
2) The resist composition according to 1), wherein Q is a bivalent organic group represented by the formula (2):
xe2x80x94R3xe2x80x94C(R5)(R6)xe2x80x94R4xe2x80x94xe2x80x83xe2x80x83(2)
wherein each of R3 and R4 which are independent of each other, is a single bond, an oxygen atom, an alkylene group having at most 3 carbon atoms, which may have an etheric oxygen atom, or a fluoroalkylene group having at most 3 carbon atoms, which may have an etheric oxygen atom, R5 is a hydrogen atom, a fluorine atom, an alkyl group having at most 3 carbon atoms or a fluoroalkyl group having at most 3 carbon atoms, and R6 is a blocked acidic group, an acidic group, or a monovalent organic group having a blocked acidic group or an acidic group.
3) The resist composition according to 1) or 2), wherein the acidic group is an acidic hydroxyl group, and the blocked acidic group is a blocked acidic hydroxyl group.
4) The resist composition according to 1), 2) or 3), wherein the fluorinated diene is a fluorinated diene represented by the formula (4) or (5):
CF2xe2x95x90CFCF2C(xe2x80x94X2)(CF3)CH2CHxe2x95x90CH2xe2x80x83xe2x80x83(4)
CF2xe2x95x90CFCF2CH(xe2x80x94(CH2)pC(CF3)2xe2x80x94X2)CH2CHxe2x95x90CH2xe2x80x83xe2x80x83(5)
wherein X2 is O(t-C4H9), OCH2OCH3, OCOO(t-C4H9), OCH(CH3)OC2H5 or a 2-tetrahydropyranyloxy group, and p is an integer of from 1 to 3.
5) A process for forming a pattern, which comprises coating the resist composition as defined in 1), 2), 3) or 4) on a substrate, then removing the organic solvent (C) to form a thin film of a resist comprising the fluoropolymer (A) and the acid-generating compound (B), and then irradiating the thin film with ultraviolet rays having a wavelength of at most 200 nm capable of generating an acid from the acid-generating compound (B) to form a pattern.
It is considered that by the cyclopolymerization of the fluorinated diene represented by the formula (1) (hereinafter referred to as the fluorinated diene (1)), the following repeating units (a) to (c) will be formed. From the results of the spectroscopic analyses, etc., the cyclized polymer of the fluorinated diene (1) is considered to be a polymer having a structure comprising repeating units (a), repeating units (b) or both of them, as the main repeating units. Here, the main chain of this cyclized polymer is meant for a carbon chain constituted by carbon atoms which constitute polymerizable unsaturated bonds (in the case of the fluorinated diene (1), the four carbon atoms which constitute polymerizable unsaturated double bonds). 
In the formula (1), each of R1 and R2 which are independent of each other, is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R1 is preferably a fluorine atom or a trifluoromethyl group. R2 is preferably a hydrogen atom or a methyl group. Q is a bivalent organic group having a blocked acidic group capable of forming an acidic group (hereinafter referred to simply as a blocked acidic group) or a group which can be converted to such a blocked acidic group (hereinafter referred to as a precursor group). In a case where Q is a bivalent organic group having the precursor group, after the cyclopolymerization of the fluorinated diene (1), the precursor groups in the polymer will be converted to blocked acidic groups.
The fluoropolymer (A) in the present invention has blocked acidic groups. In a case where the fluorinated diene (1) has a blocked acidic group, the fluoropolymer (A) can be obtained by its cyclopolymerization. In a case where the fluorinated diene (1) has the precursor groups, the fluoropolymer (A) can be obtained by converting the precursor groups in the polymer obtained by its cyclopolymerization, to blocked acidic groups. The precursor group may be an acidic group or a group which can be converted to an acidic group. The acidic group can be converted to a blocked acidic group by reacting it with a blocking agent. The group which can be converted to an acidic group, may be a blocked acidic group other than the desired blocked acidic group. By conversion of the blocked portion, it can be converted to the desired blocked acidic group. The blocked ratio of the fluoropolymer (A) (i.e. the ratio of blocked acidic groups to the total of the blocked acidic groups and non-blocked acidic groups) is preferably from 10 to 100 mol %, particularly preferably from 10 to 90 mol %.
In Q, the minimum distance between connecting bonds at its both terminals corresponds preferably to from 2 to 6 atoms, particularly preferably 2 to 4 atoms, as represented by the number of atoms (the atomic chain constituting this minimum distance will be hereinafter referred to as the main chain). The atoms constituting the main chain may be composed of carbon atoms only, or carbon atoms and other bivalent or higher valent atoms. The bivalent or higher valent atoms other than carbon atoms, may, for example, an oxygen atom, a sulfur atom and a nitrogen atom substituted by a monovalent group. An oxygen atom is particularly preferred. Such an oxygen atom or the like may be present at either one or both of the two terminals, or may be present between carbon atoms in Q.
In the main chain in Q, at least one carbon atom is present, and to a carbon atom constituting the main chain in Q, a blocked acidic group, a precursor group or an organic group containing a blocked acidic group or a precursor group, is bonded. In addition to such a specific group, hydrogen atoms or halogen atoms (particularly preferably fluorine atoms) are bonded to carbon atoms, etc. constituting the main chain, and further, an alkyl group, a fluoroalkyl group, an alkoxy group, an aryl group or other organic groups may be bonded thereto. The carbon number of such an organic group is preferably at most 6.
The acidic group may, for example, be an acidic hydroxyl group, a carboxylic group or a sulfonic group, particularly preferably an acidic hydroxyl group and a carboxylic group, most preferably an acidic hydroxyl group. The acidic hydroxyl group is a hydroxyl group showing acidity, and it may, for example, be a hydroxyl group bonded directly to the ring of an aryl group (a phenolic hydroxyl group), a hydroxyl group bonded to a carbon atom having a perfluoroalkyl group (preferably a C1-2 perfluoroalkyl group) bonded thereto, a hydroxyl group bonded to a difluoromethylene group, or a hydroxyl group bonded to a tertiary carbon atom. Particularly preferred is a hydroxyl group bonded to a carbon atom having one or two perfluoroalkyl groups bonded thereto. In a case where the perfluoroalkyl group is a trifluoromethyl group, for example, a hydroxyl group in a bivalent group of the following formula (d-1) (i.e. a hydroxyl group in a hydroxytrifluoromethylmethylene group) or a hydroxyl group in a monovalent group of the following formula (d-2) or (d-3) (i.e. a hydroxyl group in a 1-hydroxy-1-trifluoromethyl-2,2,2-trifluoroethyl group or a 1-hydroxy-1-methyl-2,2,2-trifluoroethyl group) is preferred. 
The blocked acidic group can be obtained by reacting a blocking agent to the acidic group as described above. The blocked acidic group is a group which can be converted to an acidic group by an acid which is generated by the acid-generating compound (B) which generates the acid under irradiation with light, in the resist composition. In a case where the acidic group is a carboxylic group or a sulfonic group, a blocking agent such as an alkanol may be reacted to substitute an alkyl group or the like for the hydrogen atom in the acidic group to form a blocked acidic group.
In a case where the acidic group is an acidic hydroxyl group, the blocked acidic group is preferably a blocked acidic group obtainable by substituting an alkyl group, an alkoxycarbonyl group, an acyl group, a cyclic ether group or the like for the hydrogen atom in the acidic hydroxyl group. A preferred alkyl group to be substituted for the hydrogen atom in the hydroxyl group, may be a C1-6 alkyl group which may have a substituent (such as an aryl group or an alkoxy group). Specific examples of such an alkyl group include an alkyl group having at most 6 carbon atoms (such as a tert-butyl group (t-C4H9)), an aryl group-substituted alkyl group having a total carbon number of from 7 to 20 (such as a benzyl group, a triphenylmethyl group, a p-methoxybenzyl group or a 3,4-dimethoxybenzyl group), and an alkoxyalkyl group having a total carbon number of at most 8 (such as a methoxymethyl group, a (2-methoxyethoxy)methyl group or a benzyloxymethyl group). A preferred alkoxycarbonyl group to be substituted for the hydrogen atom of the hydroxyl group, may, for example, be an alkoxycarbonyl group having a total carbon number of at most 8 or a tert-butoxycarbonyl group (xe2x80x94COO(t-C4H9)). A preferred acyl group to be substituted for the hydrogen atom of the hydroxyl group, may be an acyl group having a total carbon number of at most 8, and it may, for example, be a pivaloyl group, a benzoyl group or an acetyl group. A preferred cyclic ether group to be substituted for the hydrogen atom of the hydroxyl group, may, for example, be a tetrahydropyranyl group.
To block the acidic hydroxyl group, an alcohol, a carboxylic acid or an active derivative thereof is, for example, reacted. The active derivative thereof may, for example, be an alkyl halide, an acid chloride, an acid anhydride, a chlorocarbonic acid ester, a dialkyl dicarbonate (such as di-tert-butyl dicarbonate) or 3,4-dihydro-2H-pyran. Specific examples of the reagent useful for blocking a hydroxyl group are disclosed in Handbook of Reagents for Organic Synthesis: Activating Agents and Protecting Groups, compiled by A. J. Pearson and W. R. Roush, published by John Wiley and Sons (1999).
As the acidic group, an acidic hydroxyl group is particularly preferred, and as the blocked acidic group, a blocked acidic hydroxyl group is preferred. Specifically, as the blocked acidic hydroxyl group, O(t-C4H9), OCH2OCH3, OCOO(t-C4H9), OCH(CH3)OC2H5 or a 2-tetrahydropyranyloxy group is preferred.
Q is preferably a bivalent organic group of the following formula (2). Accordingly, the fluorinated diene (1) is preferably a compound of the following formula (3) (wherein R1 and R2 are as defined above).
xe2x80x94R3xe2x80x94C(R5)(R6)xe2x80x94R4xe2x80x94xe2x80x83xe2x80x83(2)
CF2xe2x95x90CR1xe2x80x94R3xe2x80x94C(R5)(R6)xe2x80x94R4xe2x80x94CR2xe2x95x90CH2xe2x80x83xe2x80x83(3)
wherein each of R3 and R4 which are independent of each other, is a single bond, an oxygen atom, an alkylene group having at most 3 carbon atoms, which may have an etheric oxygen atom, or a fluoroalkylene group having at most 3 carbon atoms, which may have an etheric oxygen atom, R5 is a hydrogen atom, a fluorine atom, an alkyl group having at most 3 carbon atoms, or a fluoroalkyl group having at most 3 carbon atoms, and R6 is a blocked acidic group, an acidic group, or a monovalent organic group having a blocked acidic group or an acidic group.
The alkylene group for R3 or R4 is preferably (CH2)n, and the fluoroalkylene group is preferably (CF2)m (each of m and n is an integer of from 1 to 3). In the combination of R3 and R4, it is preferred that both are alkylene groups or fluoroalkylene groups (in such a, case, m+n is preferably 2 or 3), or one of them is an alkylene group or a fluoroalkylene group, and the other is a single bond or an oxygen atom. The alkyl group for R5 is preferably a methyl group, and the fluoroalkyl group for R5 is preferably a trifluoromethyl group.
R6 in the case of a monovalent organic group, is preferably an organic group having at most 8 carbon atoms, and the moiety excluding the blocked acidic group or the acidic group, is preferably a hydrocarbon group or a fluorohydrocarbon group. Particularly preferred is a C2-6 alkyl group, a C2-6 fluoroalkyl group or a C7-9 phenylalkyl group, which has a blocked acidic group or an acid group (provided that in the phenylalkyl group, the blocked acidic group or the like is bonded to the phenyl group). Specifically, the following groups may be mentioned as R6 (wherein k is an integer of from 1 to 6, and X is a blocked acidic group or an acidic group).
xe2x80x94(CH2)kxe2x80x94X, xe2x80x94(CH2)kC(CF3)2xe2x80x94X, xe2x80x94(CH2)kC(CH3)2xe2x80x94X, xe2x80x94(CH2)kC(CF3)(CH3)xe2x80x94X, xe2x80x94(CH2)kCH(CH3)xe2x80x94X, and xe2x80x94(CH2)kC6H4xe2x80x94X.
Compounds of the following chemical formulae may be mentioned as preferred examples of the fluorinated diene (1).
CF2xe2x95x90CF(CF2)aC(xe2x80x94Y)(CF3)(CH2)bCHxe2x95x90CH2,
CF2xe2x95x90CF(CF2)aC(xe2x80x94Y)(CF3)(CF2)bCHxe2x95x90CH2,
CF2xe2x95x90CF(CH2)aC(xe2x80x94Y)(CF3)(CH2)bCHxe2x95x90CH2,
CF2xe2x95x90CF(CH2)aC(xe2x80x94Y)(CF3)(CF2)bCHxe2x95x90CH2,
CF2xe2x95x90CF(CF2)aC(xe2x80x94Y)(CF3)(CF2)bC(CH3)xe2x95x90CH2,
CF2xe2x95x90C(CF3)(CF2)aC(xe2x80x94Y)(CF3)(CF2)bCHxe2x95x90CH2,
and
CF2xe2x95x90CF(CF2)aCH(xe2x80x94Z)(CH2)bCHxe2x95x90CH2.
In the above formulae, Y is X1 or xe2x80x94R7xe2x80x94X1, Z is xe2x80x94R7X1, wherein X1 is OH, O(t-C4H9), OCH2OCH3, OCOO(t-C4H9), OCH(CH3)OC2H5 or a 2-tetrahydropyranyloxy group, and R7 is (CH2)pC(CF3)2, (CH2)pC(CF3)(CH3) or (CH2)pC6H4. Further, each of a and b which are independent of each other, is an integer of from 0 to 3 (provided that a+b is from 1 to 3), and p is an integer of from 1 to 3. The most preferred X1 is O(t-C4H9), OCH2OCH3, OCOO(t-C4H9), OCH(CH3)OC2H5 or a 2-tetrahydropyranyloxy group, and the most preferred R7 is (CH2)pC(CF3)2. Each of a and b is most preferably 1.
The most preferred fluorinated diene (1) is a compound of the following formula (4) or (5).
CF2xe2x95x90CFCF2C(xe2x80x94X2)(CF3)CH2CHxe2x95x90CH2xe2x80x83xe2x80x83(4)
CF2xe2x95x90CFCF2CH(xe2x80x94(CH2)pC(CF3)2X2)CH2CHxe2x95x90CH2xe2x80x83xe2x80x83(5)
wherein X2 is O(t-C4H9), OCH2OCH3, OCOO(t-C4H9), OCH(CH3)OC2H5 or a 2-tetrahydropyranyloxy group, and p is an integer of from 1 to 3.
The fluoropolymer (A) contains, as essential components, repeating units formed by cyclopolymerization of the fluorinated diene represented by the formula (1), but it may contain monomeric units derived from other radical polymerizable monomers within a range not to impair its characteristics. The proportion of other monomeric units is preferably at most 30 mol %, particularly preferably at most 15 mol %. Further, the fluoropolymer (A) may contain at least two types of fluorinated diene units represented by the formula (1).
Such other monomeric units may, for example, be monomeric units derived from e.g. xcex1-olefins such as ethylene, propylene and isobutylene, fluorinated olefins such as tetrafluoroethylene and hexafluoropropylene, fluorinated cyclic monomers such as perfluoro(2,2-dimethyl-1,3-dioxole, cyclopolymerizable perfluorodienes such as perfluoro(butenyl vinyl ether), (meth)acrylates such as methylacrylate and ethyl methacrylate, vinyl carboxylate esters such as vinyl acetate, vinyl benzoate and vinyl adamantylate, alkyl vinyl ethers such as ethyl vinyl ether and cyclohexyl vinyl ether, cyclic olefins such as cyclohexene, norbornene and norbornadiene, maleic anhydride, vinyl chloride, etc.
Further, a monomer having a blocked acidic group may also supplementarily be used. As such a monomer, a (meth)acrylate such as tert-butyl acrylate, tert-butyl methacrylate or tetrahydropyranyl acrylate, an alkyl vinyl ether such as tert-butyl vinyl ether, CH2xe2x95x90CHCH2C(CF3)2OCO2-t-C4H9 or CH2xe2x95x90CHCH2C(CF3)2OCH(CH3)OC2H5, may, for example, be mentioned.
The molecular weight of the fluoropolymer (A) having a cyclic structure is not particularly limited so long as it can be uniformly dissolved in an organic solvent which will be described hereinafter and it can be uniformly coated on a substrate. However, usually, its number average molecular weight as calculated as polystyrene is suitably from 1,000 to 100,000, preferably from 2,000 to 20,000. If the number average molecular weight is less than 1,000, a trouble is likely to result such that the obtainable resist pattern tends to be poor, the film remaining rate after development tends to be low, or the dimensional stability during the heat treatment of the pattern tends to deteriorate. On the other hand, if the number average molecular weight exceeds 100,000, the coating property of the composition is likely to be poor, or the developability may deteriorate.
The fluoropolymer (A) can be obtained by homopolymerizing or copolymerizing the above-mentioned monomer in the presence of a polymerization initiator. Otherwise, a fluoropolymer may be produced by using the corresponding non-blocked monomer, and then acidic groups in the fluoropolymer may be blocked by a blocking agent to obtain the fluoropolymer (A). The polymerization initiator is not particularly limited so long as it lets the polymerization reaction proceed radically. For example, it may be a radical-generating agent, light or ionizing radiation. Particularly preferred is a radical-generating agent, and a peroxide, an azo compound or a persulfate may, for example, be mentioned.
The polymerization method is also not particularly limited, and so-called bulk polymerization in which monomers are subjected to polymerization as they are, solution polymerization which is carried out in a fluorohydrocarbon, a chlorohydrocarbon, a fluorinated chlorohydrocarbon, an alcohol, a hydrocarbon or other organic solvent, capable of dissolving the monomers, suspension polymerization which is carried out in an aqueous medium in the absence or presence of a suitable organic solvent, or emulsion polymerization which is carried out by adding an emulsifier to an aqueous medium, may, for example, be mentioned.
The acid-generating compound (B) which generates an acid under irradiation with light, will cleave the blocked groups present in the polymer by the action of the acid generated by exposure. As a result, the exposed portions of the resist film will be readily soluble by an alkaline developer, whereby a positive resist pattern will be formed. As such an acid-generating compound (B) which generates an acid under irradiation with light, it is possible to employ an acid-generating compound which is commonly used for a chemical amplification type resist material. Namely, an onium salt, a halogenated compound, a diazoketone compound, a sulfone compound or a sulfonic compound, may, for example, be mentioned. The following may be mentioned as examples of such an acid-generating compound (B).
The onium salt may, for example, be an iodonium salt, a sulfonium salt, a phosphonium salt, a diazonium salt or a pyridinium salt. Specific examples of a preferred onium salt include diphenyliodonium triflate, diphenyliodonium pyrenesulfonate, diphenyliodonium dodecylbenzenesulfonate, bis(4-tert-butylphenyl)iodonium triflate, bis(4-tert-butylphenyl)iodonium dodecylbenzenesulfonate, triphenylsulfonium triflate, triphenylsulfonium hexafluoroantimonate, 1-(naphthylacetomethyl)thioranium triflate, cyclohexylmethyl(2-oxocyclohexyl)sulfonium triflate, dicyclohexyl(2-oxocyclohexyl)sulfonium triflate, dimethyl(4-hydroxynaphthyl)sulfonium tosylate, dimethyl(4-hydroxynaphthyl)sulfonium dodecylbenzenesulfonate, dimethyl(4-hydroxynaphthyl)sulfoniumnaphthalene sulfonate, triphenylsulfonium camphorsulfonate and (4-hydroxyphenyl)benzylmethylsulfonium toluenesulfonate.
The halogenated-compound may, for example, be a haloalkyl group-containing hydrocarbon compound or a haloalkyl group-containing heterocyclic compound. Specifically, it may, for example, be a (trichloromethyl)-s-triazine derivative such as phenyl-bis(trichloromethyl)-s-triazine, methoxyphenyl-bis(trichloromethyl)-s-triazine or naphthyl-bis(trichloromethyl)-s-triazine, or 1,1-bis(4-chlorophenyl)-2,2,2-trichloroethane.
The sulfone compound may, for example, xcex2-ketosulfone, xcex2-sulfonylsulfone or an xcex1-diazo compound of such a compound. Specifically, it may, for example, be 4-trisphenacylsulfone, methylphenacylsulfone or bis(phenylsulfonyl)methane. The sulfonic compound may, for example, be an alkylsulfonic acid ester, an alkylsulfonic acid imide, a haloalkylsulfonic acid ester, an arylsulfonic acid ester or an iminosulfonate. Specifically, it may, for example, be benzoin tosylate or 1,8-naphthalene dicarboxylic acid imide triflate. In the present invention, such acid-generating compounds (B) may be used alone or in combination as a mixture of two or more of them.
The organic solvent of component (C) is not particularly limited so long as it is capable of dissolving both components (A) and (B). It may, for example, be an alcohol such as methyl alcohol or ethyl alcohol, a ketone such as acetone, methyl isobutyl ketone or cyclohexanone, an acetate such as ethyl acetate or butyl acetate, an aromatic hydrocarbon such as toluene or xylene, a glycol monoalkyl ether such as propylene glycol monomethyl ether or propylene glycol monoethyl ether, or a glycol monoalkyl ether ester such as propylene glycol monomethyl ether acetate or carbitol acetate.
The proportions of the respective components in the resist composition of the present invention are usually such that per 100 parts by mass of the fluoropolymer (A), the acid-generating compound (B) is from 0.1 to 20 parts by mass, and the organic solvent (C) is from 50 to 2,000 parts by mass. Preferably, per 100 parts by mass of the fluoropolymer (A), the acid-generating compound (B) is from 0.1 to 10 parts by mass, and the organic solvent (C) is from 100 to 1,000 parts by mass.
If the amount of the acid-generating compound (B) is less than 0.1 part by mass, the sensitivity and developability tend to be poor, and if it exceeds 10 parts by mass, the transparency to radiation tends to deteriorate, whereby an accurate resist pattern will hardly be obtained.
To the resist composition of the present invention, an acid-cleavable additive to improve the pattern contrast, a surfactant to improve the coating property, a nitrogen-containing basic compound to adjust the acid-generating pattern, an adhesion-assisting agent to improve the adhesion to the substrate or a storage stabilizer to increase the storage stability of the composition, may, for example, be optionally incorporated. Further, the resist composition of the present invention is preferably employed in such a manner that the respective components are uniformly mixed, followed by filtration by means of a filter of from 0.1 to 2 xcexcm.
The resist composition of the present invention is coated on a substrate such as a silicone wafer, followed by drying to form a resist film. As the coating method, spin coating, cast coating or roll coating may, for example, be employed. The formed resist film will be irradiated with light via a mask having a pattern drawn thereon, followed by development treatment to form the pattern.
The light beams for the irradiation may, for example, be ultraviolet rays such as g-line having a wavelength of 436 nm or i-line having a wavelength of 365 nm, or far ultraviolet rays or vacuum ultraviolet rays, such as KrF excimer laser having a wavelength of 248 mm, ArF excimer laser having a wavelength of 193 nm or F2 excimer laser having a wavelength of 157 nm. The resist composition of the present invention is a resist composition useful particularly for an application where ultraviolet rays having a wavelength of at most 250 nm, especially ultraviolet rays having a wavelength of at most 200 nm (such as ArF laser or F2 laser), are used as the light source.
As the development treatment solution, various alkali aqueous solutions are employed. As such alkali, sodium hydroxide, potassium hydroxide, ammonium hydroxide, tetramethyl ammonium hydroxide or triethylamine may, for example, be mentioned.